The detachments of Territorial Defence Force (TDF, Polish: Wojska Obrony Terytorialnej) are an important element in the new structure of the Polish Army. The article presents the challenges the Territorial Defence Force, a new branch of the Armed Forces of the Republic of Poland, are currently facing. The author discusses the origin of TDF as well as the basic normative and legal documents that specify the role and tasks of TDF in the national security system. The principles of recruitment to TDF, the basic criteria laid down for candidates for service and a timeline of TDF development in 2016–2019 are described. Particular attention is paid to the cooperation between TDF and operational forces in case of an armed conflict, which poses a serious challenge to the new type of armed forces. Additionally, research suggests that the range of tasks assigned to TDF indicates their significant role within the crisis management system. This requires the TDF command to work closely with public administration and to gain trust and esteem in local communities in the regions of their operation.